The invention relates to a sealed casing provided for withstanding a certain pressure and intended to contain notably an electric accumulator, the casing being formed by at least one wall which has at least one closing area formed by a plastic band for connecting two edges of the wall.
The invention also relates to a flat accumulator formed from such a casing.
The invention finds highly significant applications, for example, for containing an accumulator of the lithium-ion or lead-acid type.
U.S. Pat. No. 5,326,652 describes such an accumulator and its casing. However, in that document, the problem of internal pressure of the accumulator is not mentioned. Indeed, the accumulators create pressures inside the envelopes formed by the casings containing them. This pressure may sometimes be so high that the envelope explodes, which is very dangerous, above all if the accumulator is of the type containing lithium. Therefore, valves may be provided which open when the variation of pressure exceeds a certain value that is incompatible with the solidity of this envelope.